In-Line Fan Assembly

ABSTRACT

An airflow electrical generator for a duct system. The electrical generator is located outside the duct. The axle of the electrical generator is vertical to the airflow within the duct allowing the blades of the generator to be pushed downwind along the duct with the airflow. During the “upwind” movement of the blades, the blades pass outside the duct&#39;s profile into a closely fitting plenum allowing each blade to travel outside the airflow and all the low-pressure created by the movement of each blade within the plenum to pull the following blade for improved efficiency.

Priority for this application is claimed from Provisional Patent application Ser. No. 62/392,748, filed on Jun. 10, 2016, and entitled “In-Line Fan Assembly”.

BACKGROUND OF THE INVENTION

This invention relates generally to electrical generation mechanism and more particularly to air powered electrical generation.

Renewable energy is very much on the forefront of modern thinking. Worries over pollution, global warming, and limited fossil fuels has spurred massive research in solar, geothermal, and wind generated electrical power.

In the field of wind or air powered electrical generation, the universal standard has been to place all of the blades of the fan perpendicular to the airflow stream. This assures that all of the blades are receiving force from the airflow; but, it also means that the generator itself is positioned in the airstream.

Positioning the blades perpendicular to the wind isn't a major obstacle for wind generators where the blades are in excess off fifty feet in length, in the case where the airflow being captured in within a duct, the electrical generator's own cross section profile causes significant resistance to the airflow.

It is clear from the foregoing that there is a need more efficient electrical generator using wind power.

SUMMARY OF THE INVENTION

The invention is an airflow electrical generator for a duct system. Ducting is used throughout daily life being found in everything from buildings to automobiles. Ducts typically carry air which is going to be used (e.g. air conditioning or heating systems) or which is being discharged (e.g. exhaust from an automobile). These are the situations where the present invention is most useful for the generation of electrical energy by capturing the force of the airflow.

The electrical generator is located outside the duct. This assists not only in reducing “drag” within the duct's airflow, but also in protecting the electrical generator from damage which may be caused by the airflow.

The axle of the electrical generator is vertical to the airflow within the duct allowing the blades of the generator to be pushed “downwind” along the duct with the airflow. During the “upwind” movement of the blades, the blades pass outside the duct's profile. This allows the upward moving blades to be totally unaffected by the airflow.

When the blades are outside the duct's profile, ideally, they pass through a closely fitting plenum allowing the low-pressure created by the movement of each blade within the plenum to “pull” the following blade for improved efficiency.

The invention, together with various embodiments will be more fully explained by the accompanying drawings and the following description thereof.

DRAWINGS IN BRIEF

FIG. 1A is a top view of the preferred embodiment; FIG. 1B is a side view thereof.

FIG. 2 illustrates an alternative embodiment of the invention.

FIGS. 3A, 3B, and 3C illustrate alternative fan blades of the invention.

DRAWINGS IN DETAIL

FIG. 1A is a top view of the preferred embodiment; FIG. 1B is a side view thereof.

Duct 10 has an airflow 11 therethrough. This airflow 11 impacts on any exposed blades within duct 10 of fan 16 which rotates (15B) around axle 18 which is positioned vertical to airflow 11. Blades 16 rotates “downwind” as indicated by arrow 15B and on the “upwind” cycle, leave duct 10 and enter plenum 13.

Note that ideally, plenum 13 “hugs” blade 12 to minimize wind resistance therein.

While in plenum 13, the blades, such as blade 12, on entering zone 14A of the plenum, are not exposed by airflow 11 and as such experience little or no resistance. Further, as blade 12 moves within plenum 13, a “low pressure” zone behind it is created which attempts to pull the following blade

This high pressure/low pressure usage in the present invention is enhanced with the use of bevel 19 which causes the airflow to divert away from plenum 13 as illustrated by arrow 15A. This diversion of the airflow causes a “low pressure” zone in zone 14B of plenum 13 to “pull” blade 12 into airstream 11 of duct 10.

As axle 18 rotates, electrical generators 17A and 17B produce electricity which is used immediately or stored for later use. Note, in this illustration, there are two generators illustrated, but, the invention is not so limited but can include any number of generators being operable by axle 18.

Another point to note is that axle 18, in this preferred embodiment lies entirely within plenum 13. This embodiment creates a minimal amount of airflow disturbance.

FIG. 2 illustrates an alternative embodiment of the invention.

This embodiment also employs the use of plenum 22 and duct 20 as described above. In this embodiment though, axle 21 is positioned outside of plenum 22 and within duct 20.

Those of ordinary skill in the art readily recognize that the placement of the axle can be entirely in duct 20, plenum 22, or part in each.

FIGS. 3A, 3B, and 3C illustrate alternative fan blades of the invention.

The blade 30 of FIG. 3A has a “spoon” arrangement 31 at the end to assist in capturing the full force of the airflow. The opposing “downwind” side, not shown, is curved to even further reduce the resistance during the “upwind” action within the plenum.

Blade 32 of FIG. 3B is a typical “propeller” shape.

Blade 33 of FIG. 3C has an extended “cup” 34 for full capture of the airflow.

Those of ordinary skill in the art readily recognize a variety of other blade shapes which can be utilized in this context.

It is clear that the invention creates an improved wind powered electrical generator. 

What is claimed is:
 1. A fan assembly engaging an airflow, said fan assembly comprising: a) a fan having, 1) a central axle positioned perpendicular to the airflow, and, 2) a multitude of blades secured to the central axle and positioned to selectively engage the airflow, such that the blades so engaged travel in the airflow direction and cause said central axle to rotate; and, b) a generally semi-circular plenum positioned external to the airflow and positioned such that during rotation of the central axle, each of said multitude of blades passes through the generally semi-circular plenum.
 2. The fan assembly according to claim 1, further including a bevel positioned to direct the airflow away from the generally semi-circular plenum.
 3. The fan assembly according to claim 2, wherein each of said multitude of blades are configured for resistance to the airflow.
 4. The fan assembly according to claim 2, wherein said central axle is positioned to extend through the plenum.
 5. The fan assembly according to claim 2, further including a duct encasing the airflow and wherein the plenum is secured to said duct.
 6. The fan assembly according to claim 5, wherein said central axle is positioned to extend through the duct.
 7. The fan assembly according to claim 5, wherein said central axle is secured to and drives a secondary mechanism.
 8. A mechanism comprising: a) a fan having a central axle positioned perpendicular to an airflow, said central axle having a multitude of blades secured thereto; b) A semi-circular plenum positioned outside the airflow and positioned such that during rotation of the central axle, each of said multitude of blades passes through the plenum and at a different position engages the airflow; and, c) a bevel adapted to create air pressure within the plenum less than an air pressure of the airflow.
 9. The mechanism according to claim 8, wherein each of said multitude of blades are shaped for resistance to the airflow and reduced resistance when traveling through the plenum.
 10. The mechanism according to claim 9, wherein said central axle is positioned to extend through the plenum.
 11. The mechanism according to claim 9, further including a linear duct encasing the airflow and wherein the plenum is secured to said linear duct.
 12. The mechanism according to claim 11, wherein said central axle is positioned to extend through the linear duct.
 13. An electrical generator comprising: a) a fan having, 1) a central axle positioned perpendicular to an airflow, and, 2) a multitude of blades secured to the central axle and positioned to selectively engage the airflow, such that blades so engaged, travel in a direction of the airflow and cause said central axle to rotate; b) an airflow free plenum positioned such that during rotation of the axle, each of said multitude of blades at some point in their rotation passes through the plenum removed from the airflow; and, c) at least one generator secured to the central axle such that rotation of the central axle causes said at least one generator to produce electricity.
 14. The electrical generator according to claim 13, wherein each of said multitude of blades are configured for resistance to the airflow.
 15. The electrical generator according to claim 14, wherein said plenum restricts airflow therethrough.
 16. The electrical generator according to claim 15 wherein said plenum has a generally semi-circular cross section.
 17. The electrical generator according to claim 16, wherein said central axle is positioned to extend into the plenum.
 18. The electrical generator according to claim 16, further including a duct encasing the airflow and wherein the plenum is secured to said duct.
 19. The electrical generator according to claim 18, wherein said central axle is positioned to extend into the duct. 